Passage Summary: Biologists once thought rabbits could reproduce without fertilization, but that study was bad and no one has proven it since. Because we see it in other animals but haven't seen it in mammals yet, the author concludes it must be biologically impossible for mammals.

Conclusion: Mammalian chromosomes must contain a specific feature that makes reproduction without fertilization impossible.

Reasoning: An old study claiming it happened was flawed, no subsequent studies have proven it occurs in mammals, yet it is known to occur in other types of animals.

Analysis: This is a classic 'absence of evidence' flaw. Just because we haven't successfully proven that something does happen doesn't mean we have proven that it cannot happen. The author leaps from 'we haven't found it' to 'it's impossible,' which is a major logical overstep. Look for an answer that highlights this confusion between a lack of proof and proof of the opposite.